1. Field Of The Invention
This invention relates to an improved air filtration unit having a non-rotatable drum around which advances a thin textile filter medium. This device is useful in industrial plants such as textile mills where cotton dust is a major air contaminant.
2. Description Of The Prior Art And Objectives Of The Invention
Various prior art devices have been developed through the years for use in factories, textile and other mills, office buildings and other enclosed structures to remove one or more contaminants from the air which is breathed by workers. Such air filter units have their own fans for pulling air through a filter medium and for exhausting the filtered air back into the room. Conventional units generally operate at high static pressure (11/4-11/2 inches of H.sub.2 O) and require a fan having a motor rated at 2 or more horsepower to achieve the desired contaminant reduction results. Also, many prior art devices may require a 1 horsepower or a larger electric motor to advance the filter medium. Conventional filtration units may also require a hood or cover to protect the unrolled or fresh filter medium from contamination before use and enclosing the filter medium supply can cause difficulty during removing or changing the filter medium when needed.
With these problems and disadvantages known of conventional air filtration units the present invention was conceived and one of its objectives is to provide an air filter which will operate effectively at 0.8 inch of static pressure (H.sub.2 O) with the use of 2 centrifugal fans each having 1/3 horsepower 110 volt electric motors.
It is another objective of the present invention to provide an air filter which is economical to build and which is relatively simple to maintain in operation.
It is still another objective of the present invention to provide an air filter in which maintenance personnel can easily detect any problems which may arise and can easily change the filter medium supply when necessary.
It is yet another objective of the present invention to provide an air filter having a filter medium supply, a non-rotatable drum and a take-up roller whereby the filter medium from the supply passes around the drum and back over the filter medium supply thereby protecting medium supply from contamination.
It is still yet another objective of the present invention to provide an air filter in which a small horsepower motor can be used to advance the filter medium since the filter medium supply roll provides an axis of rotation.
It is another object of the present invention to provide a method for filtering air comprising extending filter medium from a medium supply to a support drum, wrapping the support drum with medium, returning the medium from the drum along the outer periphery of the medium supply and on to a take-up roller whereby contaminated air passes through the filter medium and support drum thereby removing contaminants therein.
Various other advantages and objectives of the present invention become apparent to those skilled in the art as a more detailed description of the invention is set forth below.